From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 19 Sep 2013 01:51:23 +0000 (+0000)
Subject: Fix use-after-free in r190980.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0f238a61be7ba8a52383fc3419889d52431316d4;p=clang

Fix use-after-free in r190980.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190984 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 2570755cbd..e6b6b1fe1c 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -2823,9 +2823,12 @@ bool Lexer::Lex(Token &Result) {
 
   bool atPhysicalStartOfLine = IsAtPhysicalStartOfLine;
   IsAtPhysicalStartOfLine = false;
-  bool result = LexTokenInternal(Result, atPhysicalStartOfLine);
-  assert((result || !isLexingRawMode()) && "Raw lex must succeed");
-  return result;
+  bool isRawLex = isLexingRawMode();
+  (void) isRawLex;
+  bool returnedToken = LexTokenInternal(Result, atPhysicalStartOfLine);
+  // (After the LexTokenInternal call, the lexer might be destroyed.)
+  assert((returnedToken || !isRawLex) && "Raw lex must succeed");
+  return returnedToken;
 }
 
 /// LexTokenInternal - This implements a simple C family lexer.  It is an